Trolls are not known for their standing around passively in combat. If your niece, twice removed, that you have been hocking up with for the past 10 years and have fought with many times, is suddenly standing around digging up boogers, right after some tasty looking human shouted at her while a soft golden glow enveloped her...even a moronic hill billy troll is going to realize there is something wrong...
I do agree that as a player it is undesirable to cast spells you haven't been conferring about with your GM. My houserule on that is that if you do that, expect the result to be less than desirable. Even though I want to follow the RAW as much as possible (and usually there is not much interpretation needed to curb the spell), if there is an issue, it should be fixed. Issues arise from liberal interpretation.
I read a spell like calm as follows: will do anything else in their power, except offensive aggressive actions: so buffs, advice, trying to hug the PCs "Me so calm...me hug nice plant lady now", arming traps (not pulling attack delivery levers though), shielding friends, parley, play a game, gymnastics, escape, trap the PC, lying and cheating, etc is all fair game. Calm is a low level spell with good effect, but it shouldn't be like a lvl 20 spell taking out most combatants in a single spell. There is plenty for the GM (and the players) to circumvent the RAW description. Even lighting the fuse on a cannon/ bomb might qualify. Then there's orders given from the non calmed adversaries; if they are not aggressive, can be followed. Apathy is such a nasty effect, it can't be the effect of such a low level spell.
Also I would not give quarter to PCs taking advantage of the spell: I would allow defensive actions for the calmed creature if their babies or eggs were stolen/ harmed, also if a PC attacks a creature and then withdraws, the calmed creature will pursue and "defend" itself against that PC until either is incapacitated.
Anything is allowed to disuade PCs from using such spells to "fix" the game in their favor.